Saturday, October 20, 2007

Last night I had a conversation with some faculty friends about teaching. We reached the common point where some of us were saying that students shouldn't have to memorize lists of facts, and others were saying that students need to know the facts before they can begin to think about what they mean. One of us made the important point that the word 'memorize' may mean different things to different people, and different things in different contexts, which (slowly) got me thinking about how we can be more clear.

We all want our students to remember the facts we think important. When we complain that students are memorizing rather than learning (student readers of this blog should note that we are just as likely to be blaming the teachers as the students for this), we mean to distinguish 'rote memorization' from our more-or-less vague concept of 'real learning'. Maybe we could speak of 'remembering without understanding' and remembering with understanding'.

I'll use the cell-division process of meiosis as an example. Students are often expected to be able to define meiosis, name the stages of meiosis and reproduce the textbook illustrations of these stages. But students can accomplish this by rote memorization or as part of a richer remembering. A student who 'really understood' meiosis might be able to explain how the consequences of meiosis differ from those of mitosis and what role this difference plays in reproduction. They might be able to draw steps intermediate between the defined stages, or move paper chromosomes to simulate the entire process. They might be able to explain the physical forces and interactions that bring about the different stages, and how the genetics principles called 'Mendel's rules' are a consequence of what happens to chromosomes in meiosis.

I'll try another example, brought up by a botanist who teaches students about how the different parts of plants transport water and nutrients. Students could simply rote-memorize the names of the structures (phloem, xylem, cambium, stomata, root hairs...) and be able to reproduce textbook definitions and drawings of them, complete with labels of the substances transported and the directions of flow. Or they could also be able to explain why plants need root hairs, why some substances move up the phloem and others down the xylem (or vice versa?), which parts of this transport consume energy and why other parts don't.

Of course a student could have used rote memorization to remember all this information. And we often test students' learning in ways that can be satisfied by rote memorization, probably because this is much easier for us to assess than is deeper understanding. Our Physics colleagues have been discovering that tests that they thought were assessing understanding were in fact being passed by rote memorization. Students could 'plug and chug' - getting the answer to a question of a recognized type by inserting numbers into a memorized formula. When physicists began to assess students' understanding by putting the phenomena into new (simpler and more familiar) contexts where formulas weren't useful, they discovered that the students could no longer answer the questions. So now Physics faculty are leading the way in devising ways to measure genuine understanding, and using these measures to identify and change weaknesses in their teaching.

In Biology we of course do try to test understanding, not just memorization. We do this by asking such questions as "Would anything go wrong if a cell started meiosis with three copies of one of its chromosomes?" or "Would a plant growing in a greenhouse on Mars need the same number of root hairs as one growing under identical conditions (light, water, nutrients, atmosphere) on Earth?" One reason that I give only open-book exams is to discourage myself from asking questions whose answers can simply be looked up in the book.

One big question for Biology faculty is whether our students should be asked to rote-memorize some information before they develop their understanding of its importance, or whether the remembering should only be built up (and assessed) as part of the understanding. I favour the latter. I have been thinking that some of my colleagues disagree, but this may be only because we've meant different things by the word 'memorize'.

For first-year students, examples from the textbook or from everyday life are likely to be most appropriate.

Students should also be able to identify situations where the experimental design and/or results mean that no conclusion can be made.

Communication skills:Students should be able to construct a logical and clearly expressed argument supporting a statement.

A Short Guide to Writing about Biology (Jan. A. Pechenik) is an excellent resource for writing assignments. Instructors may choose to require their students to obtain it and use it as a framework for one or more assignments.

Some instruction should be provided in class, possibly with examples of better and worse writing, but the actual writing can be done outside of class and assessed with WebCT, through the Help Centre or by peer review.

Students should also be given experience in verbal communication and group work by having opportunities to explain a concept to another student or small group of students.

Study skillsStudents should be able to make effective use of textbooks, including the table of contents, glossary, end-of-chapter summaries, figures and diagrams, and study questions.

Students benefit from practice in constructing hierarchical summaries of information provided in textbooks and in lectures.

Interpreting an unlabelled diagram is a good exercise.

A textbook-based scavenger hunt for information is a good in-class exercise that could be done multiple times on different topics.

Societal context of science:Students should be able to identify scientific issues relevant to societal problems, and societal issues arising out of scientific advances.

Instructors may wish to choose one issue relevant to course material for in-depth consideration by the class, or have students consider a number of issues throughout the course.

It is important that students gain experience in discovering the issues themselves, rather than simply learning about issues presented by the instructor.